1. Field of the Invention
The present invention relates to a liquid discharge cartridge with the structure of having a liquid discharge element and a switching circuit, including a liquid discharge head applicable to an apparatus used for the production of a DNA chip, an organic transistor, a color filter, or the like, and a liquid container which contains liquid supplied to this. The liquid discharge head discharges liquid by injecting energy into a liquid discharge element and makes liquid droplets adhere on a medium, and in particular, relates to an ink jet recording head using ink as the liquid.
2. Related Background Art
A liquid discharge apparatus will be explained with an example of an ink jet recording apparatus. One of structures of detecting residual ink amount in an ink tank in a conventional ink jet recording apparatus (ink jet printer) will be explained. First, the change of the electrostatic capacitance which varies according to ink residual amount is converted into an output signal (pulse signal) in an oscillation circuit provided in a CR circuit, and is outputted. The output signal is inputted into a central processing unit (hereinafter, a “CPU”) of a host computer which controls the printer. Then, the structure of detecting the change of a frequency of the pulse signal and detecting the residual ink amount in the CPU is known.
In this conventional structure, since the output signal outputted from the oscillation circuit is directly inputted into the CPU of the host computer, there is a problem that the processing burden of the CPU of the host computer becomes heavy. Then, in order to solve this problem, the structure relating to Japanese Patent Application Laid-Open No. H10-100447 has been proposed.
FIG. 10 is a circuit diagram of residual ink amount detection equipment shown in the above-mentioned gazette. A signal A is outputted from an electrostatic detection circuit 1051 where an oscillation frequency varies according to the residual ink amount in an ink tank 1057. Then, a signal B is outputted from a reference signal generating circuit 1039. The logical operation of them is performed in a NAND circuit 1040, and the CPU compares an output signal C of the NAND circuit 1040 to the signal B. Thereby, the load of the CPU is reduced in comparison to the structure that the output signal outputted from the oscillation circuit is directly inputted into the CPU of the host computer. Then, it becomes possible to enhance processing speed as a whole.
In addition, some printers are constituted so as to count the number of times of discharge of ink by each CPU and may estimate residual ink amount. An ink jet unit being equipped with an memory element in which the number of drive pulses expressing the number of times of ink discharge and the number of times of suction recovery treatment are written is disclosed in Japanese Patent Application Laid-Open No. H09-314861. FIG. 11 is a drawing showing in multiple the structure of a conventional ink jet unit shown in the above-mentioned gazette.
The ink jet unit shown in FIG. 11 is formed by integrating a head 2010 and an ink tank 2014. This unit is mounted detachably in a carriage (not shown) of a recording apparatus. In the drawing, a memory element 2011 is constituted of, for example, EEPROM (Electrically Erasable Programmable Read-only Memory) which is nonvolatile memory. The memory element 2011 is mounted on a PCB substrate 2012, and a plurality of heat-generating resistors (not shown) are provided on a silicon substrate 2013 corresponding to the number of ink ejection orifices. The silicon substrate 2013 and PCB substrate 2012 are electrically connected by wire bonding. A terminal 2015 is provided in an end portion of the PCB substrate 2012, and electrically connects a head 2010 to an apparatus body. When being mounted in the carriage, the ink jet unit is connected to a connector provided on the carriage. The head 2010 is equipped with the above-mentioned respective elements. On the other hand, an ink tank 2014 stores ink supplied to the head 2010.
According to this structure, the number of drive pulses expressing the number of times of ink discharge, and the number of times of suction recovery treatment are written in the memory element 2011 in the head 2010. Thus, accumulated values such as the number of drive pulses relating to ink amount consumed by the head 2010 are stored. In order to know residual ink amount, data is first fetched from the memory element 2011 by read and write means provided in the recording apparatus. Then, a CPU of the recording apparatus or the like subtracts ink consumption corresponding to the number of drive pulses and the number of times of suction recovery treatment, which are recorded in the data, from the initial ink amount of the ink tank 2014. Owing to this, it becomes possible to know the residual ink amount in the ink tank 2014. In addition, when the memory element 2011 is nonvolatile memory such as EEPROM, the information stored in the memory element 2011 is not erased even if the ink jet unit is removed from the recording apparatus.
In addition, U.S. Pat. No. 6,719,394 discloses the structure of arranging a ball-shaped semiconductor device in the interior or exterior of a container such as an ink tank, and detecting information inside the ink tank. This device is equipped with energy conversion means, information acquisition means of acquiring environmental information around the device, and judgment means. Furthermore, the device is equipped with information storage means of accumulating information for being compared with the information, acquired by the information acquisition means, by the judgment means, and information transmission means 18 of transmitting the acquired information to the outside by the judgment of the judgment means 16.
Nevertheless, the conventional residual ink amount detection equipment shown in FIG. 10 cannot detect the residual ink amount without using the CPU of the host computer. Therefore, a processing burden arises in the CPU of the host computer, and in order to detect the residual ink amount, a user has to start both the host computer and recording apparatus, and hence, this is inconvenient for a user. Nevertheless, when the processing capability currently performed by the CPU is separately installed in the recording apparatus in order to detect the residual ink amount, the cost of the recording apparatus increases.
In addition, in the structure of counting the number of times of discharge of ink and estimating the residual ink amount by a CPU of a recording apparatus as shown in FIG. 11, a processing burden also arises in the CPU of the recording apparatus.
In addition, in the structure in U.S. Pat. No. 6,719,394, it is necessary separately to provide a three-dimensional semiconductor device. Furthermore, since a drive power supply also has the structure of converting external force and the like into energy by energy conversion means, structure is complicated, and hence, the further simplification of a detection system is required.
Then, the present invention aims at providing a liquid discharge cartridge with the structure that information about the presence of residual liquid amount stored in the memory of the liquid discharge cartridge is not erased even if the liquid discharge cartridge is removed from a liquid discharge apparatus, and that a processing burden is not made to arise in a CPU of a host computer or the liquid discharge apparatus.